Grade powders and sintered cemented carbide compositions

ABSTRACT

In one aspect, grade powder compositions are described herein comprising electrochemically processed sintered carbide scrap. In some embodiments, a grade powder composition comprises a reclaimed powder component in an amount of at least 75 weight percent of the grade powder composition, wherein the reclaimed carbide component comprises electrochemically processed sintered carbide scrap.

FIELD

The present invention relates to grade powders and associated sinteredcemented carbide compositions and, in particular, to grade powders andsintered cemented carbide compositions comprising electrochemicallyprocessed sintered carbide scrap.

BACKGROUND

Tungsten is an industrially significant metal finding application in avariety of fields with particular emphasis in the tooling industry. Thehigh hardness, heat resistance and wear resistance of tungsten and itscarbide form make it an ideal candidate for use in cutting tools, miningand civil engineering tools and forming tools, such as molds andpunches. Cemented tungsten carbide tools, for example, account for themajority of worldwide tungsten consumption. According a 2007 UnitedStates Geological Survey, mineral deposits of tungsten resources totaledin the neighborhood of nearly 3 million tons. At current productionlevels, these resources will face exhaustion within the next fortyyears. Moreover, a handful of nations control the majority of worldwidetungsten deposits. China, for example, controls approximately 62% oftungsten deposits and accounts for 85% of ore production volume.

Given the limited supply of tungsten and its inequitable globaldistribution, significant resources have been invested in thedevelopment of processes for recycling scrap tungsten carbidecompositions. For example, hydrometallurgy tungsten recycling processeshave been developed where tungsten carbide scrap is roasted with moltensodium nitrate (NaNO₃) to generate water soluble Na₂WO₄. The Na₂WO₄undergoes conversion to several different chemical species ending in anaqueous solution of (NH₄)₂WO₄. Ammonium paratungstate (APT) can beeasily converted to tungsten oxide (WO₃) by roasting and subsequentlycarburized to tungsten carbide (WC). This recycling process, however,demonstrates several disadvantages including numerous processing steps,high chemical consumption and high energy consumption. Therefore,profitability is limited until large scale production is achieved.

An alternative process for recycling WC scrap employs molten zinc metal.In this process, cemented carbide scrap is mixed with zinc ingots in atray, and the mixture is heated in a furnace to liquefy the zinc. Theliquefied zinc permeates the WC scrap reacting with the metallic binderphase. The zinc is subsequently volatilized leaving behind a porous WCthat is crushed into powder form. This zinc treatment process alsosuffers significant disadvantages. Liquefication of the zinc, forexample, requires high energy consumption. More troubling, however, isthe dirty state of the resulting porous WC. Zinc treatment does notremove impurities in the WC composition such as metal carbide graingrowth inhibitors and metallic binder. Such impurities result ininferior mechanical and chemical properties, thereby limiting use of therecycled WC composition in the fabrication of new tooling.

SUMMARY

In one aspect, grade powder compositions are described herein comprisingelectrochemically processed sintered carbide scrap. In contrast to otherreclamation or recycling techniques, electrochemical processing canremove substantial amounts of metallic binder and other impurities fromthe sintered carbide scrap. Removal of these impurities providessignificant flexibility to combine the electrochemically processedsintered carbide scrap with fresh powder metallic binder and othercomponents to provide new grade powder compositions for production ofsintered cemented carbide parts. In some embodiments, for example, agrade powder composition comprises a reclaimed carbide powder componentin an amount of at least 70 weight percent of the grade powdercomposition, wherein the reclaimed carbide powder component compriseselectrochemically processed sintered carbide scrap. Theelectrochemically processed sintered carbide scrap can comprise tungstencarbide. In some embodiments, the reclaimed carbide powder componentconsists essentially of the electrochemically processed sintered carbidescrap. The grade powder composition can also comprise powder metallicbinder.

In another aspect, sintered cemented carbide articles are describedherein. A sintered cemented carbide article comprises a reclaimedcarbide phase in an amount of at least 70 weight percent of the sinteredarticle, the reclaimed carbide phase comprising electrochemicallyprocessed sintered carbide scrap. In some embodiments, the reclaimedcarbide phase consists essentially of the electrochemically processedsintered carbide scrap. The sintered cemented carbide article alsocomprises metallic binder. Moreover, the sintered cemented carbidearticle can exhibit fracture toughness of 5-20 ksi(in^(1/2)), in someembodiments. The sintered cemented carbide article may also havetransverse rupture strength of 250-650 ksi.

In another aspect, methods of making sintered cemented carbide articlesare provided. In some embodiments, a method of making a sinteredcemented carbide article comprises providing a grade powder compositioncomprising powder metallic binder and a reclaimed carbide powdercomponent in an amount of at least 70 weight percent of the grade powdercomposition, the reclaimed carbide powder component comprisingelectrochemically processed sintered carbide scrap. The grade powdercomposition is formed into a green article, and the green article issintered to provide the sintered cemented carbide article.

These and other embodiments are further described in the followingdetailed description.

DETAILED DESCRIPTION

Embodiments described herein can be understood more readily by referenceto the following detailed description and examples and their previousand following descriptions. Elements and apparatus described herein,however, are not limited to the specific embodiments presented in thedetailed description. It should be recognized that these embodiments aremerely illustrative of the principles of the present invention. Numerousmodifications and adaptations will be readily apparent to those of skillin the art without departing from the spirit and scope of the invention.

I. Grade Powder Compositions

In one aspect, grade powder compositions are described herein comprisingelectrochemically processed sintered carbide scrap. In some embodiments,a grade powder composition comprises a reclaimed carbide powdercomponent in an amount of at least 70 weight percent or at least 75weight percent of the grade powder composition, wherein the reclaimedcarbide powder component comprises electrochemically processed sinteredcarbide scrap. In some embodiments, the reclaimed carbide powdercomponent is present in an amount of 80-99 weight percent or 90-99weight percent of the grade powder composition. The grade powdercomposition also comprises powder metallic binder.

Turning now to specific components, the reclaimed carbide powdercomponent comprises electrochemically processed sintered carbide scrap.As described herein, electrochemical processing can remove substantialamounts of metallic binder and/or other impurities from the sinteredcarbide scrap. In some embodiments, the electrochemically processedsintered carbide scrap has physical, mechanical and/or chemicalproperties substantially similar to virgin carbide. Accordingly,significant flexibility exists to combine the electrochemicallyprocessed sintered carbide scrap with fresh powder metallic binder andother components to provide new grade powder compositions for productionof sintered cemented carbide parts. In some embodiments, theelectrochemically processed sintered carbide scrap is limited totungsten carbide particles. In other embodiments, the electrochemicallyprocessed sintered carbide scrap comprises tungsten carbide and one ormore metal carbides selected from the group consisting of Group IVBmetal carbides, Group VB metal carbides and Group VIB metal carbides.

The electrochemically processed sintered carbide scrap can have anyaverage particle size not inconsistent with the objectives of thepresent invention. In some embodiments, the electrochemically processedsintered carbide scrap has an average particle size of 0.5 μm to 30 μm.In other embodiments, the electrochemically processed sintered carbidescrap has an average particle size of 1 μm to 5 μm. Desired particlesize of the electrochemically processed sintered carbide scrap can beachieved by milling the sintered carbide scrap with powder metallicbinder in the production of the grade powder. The milled grade powdercan be spray dried or vacuum dried and granulated to providefree-flowing powder aggregates of various shape, including sphericalshape. Alternatively, the grade powder can be vacuum dried to providepowder suitable for isostatic compaction. In some embodiments, theelectrochemically processed sintered carbide scrap can be crushed orotherwise comminuted prior to milling with the metallic binder. Sinteredcarbide scrap can be processed by a variety of electrochemicaltechniques including, but not limited, to the electrochemical techniquesdescribed in U.S. Pat. No. 9,656,873 which is incorporated herein byreference in its entirety. Electrochemically processed sintered carbidescrap is also available from various commercial sources including GlobalTungsten and Powders Corporation of Towanda, Pa.

In some embodiments, the reclaimed carbide powder component consistsessentially of the electrochemically processed sintered carbide scrap.For example, in one embodiment, the electrochemically processed sinteredcarbide scrap is the sole species of the reclaimed powder component.Alternatively, the reclaimed carbide powder component compriseselectrochemically processed sintered carbide scrap and sintered carbidescrap processed by one or more different reclamation methods. In someembodiments, APT processed and/or zinc processed sintered carbide scrapcan be combined or mixed with electrochemically processed sinteredcarbide scrap to provide the reclaimed carbide powder component of thegrade powder composition. The electrochemically processed sinteredcarbide scrap can be mixed with other reclaimed sintered carbide scrapin any amount not inconsistent with the objectives of the presentinvention. Amount of electrochemically processed sintered carbide scrapin the reclaimed carbide powder component can be selected according toseveral considerations including the desired mechanical and chemicalproperties of articles formed from the grade powder and thecompositional identity of other powders in the reclaimed carbide powdercomponent. In some embodiments, electrochemically processed sinteredcarbide scrap is present in an amount of 50-100 weight percent of thereclaimed carbide component. Electrochemically processed sinteredcarbide scrap can also be present in the reclaimed carbide powdercomponent at a weight percent selected from Table I. The remainingweight percent of the reclaimed carbide powder component is filled byother reclaimed sintered carbide scrap, such as APT and/or zincprocessed sintered carbide scrap.

TABLE I wt. % of Electrochemically Processed Sintered Carbide Scrap40-99 50-85 50-75 60-90 70-95

In some embodiments, the grade powder can further include a virgincarbide component. The virgin carbide component can comprise carbides,nitrides and/or carbonitrides of one or more metals selected from GroupsIVB, VB and VIB of the Periodic Table. In being virgin, the metalcarbides, nitrides and/or carbonitrides have not previously been part ofa sintered carbide composition. In some embodiments, the virgin carbidecomponent comprises at least one of tungsten carbide, tantalum carbide,niobium carbide, vanadium carbide, chromium carbide, zirconium carbide,hafnium carbide, titanium carbide and solid solutions thereof. Thevirgin carbide component can be present in the grade powder compositionin any amount not inconsistent with the objectives of the presentinvention. Amount of virgin carbide component can be selected accordingto several considerations including, but not limited to, desiredmechanical and chemical properties of sintered articles formed of thegrade powder and specific compositional identity of the reclaimedcarbide powder component. In some embodiments, the virgin carbidecomponent is present in an amount of 0-20 weight percent of the gradecomposition, such as 0.1-20 weight percent.

The grade composition also comprises powder metallic binder. The powdermetallic binder can comprise one or more transition metals, includingmetals of Group VIIIB of the Periodic Table. In some embodiments, forexample, the powder metallic binder is cobalt or cobalt-based alloy.Power cobalt-based alloy binder, in some embodiments, comprises acobalt-transition metal alloy. For example, transition metal of thebinder alloy can be selected from the group consisting of molybdenum,ruthenium, rhenium, rhodium, platinum, palladium, manganese, copper,iron, nickel and combinations thereof. In other embodiments, powdercobalt-based metallic binder comprises silicon and/or aluminum. Thepowder metallic binder can be present in the grade powder in any amountnot inconsistent with the objectives of the present invention. Themetallic binder can be present in an amount of 1 weight percent to 30weight percent of the grade powder composition. In some embodiments,metallic binder is present in the grade powder composition in an amountselected from Table II.

TABLE II Amount of Co-based metallic binder (wt. %) 1-25 5-20 5-1510-15  12-14 The powder metallic binder coats carbide components of the grade powdercomposition, including individual particles of the reclaimed carbidepowder component and virgin carbide component, if present.

II. Sintered Cemented Carbide Articles

In another aspect, sintered cemented carbide articles formed from gradepowder compositions described in Section I herein are provided. Asintered cemented carbide article, for example, comprises a reclaimedcarbide phase in an amount of at least 70 weight percent of the sinteredarticle, the reclaimed carbide phase comprising electrochemicallyprocessed sintered carbide scrap. The sintered cemented carbide articlealso comprises metallic binder. The sintered cemented carbide articlescan comprise any of the grade powder composition properties described inSection I. For example, the reclaimed carbide phase can be present in anamount of 80-99 weight percent or 90-99 weight percent of the sinteredcemented carbide article. Moreover, the reclaimed carbide phase canconsist essentially of electrochemically processed sintered carbidescrap. Alternatively, the reclaimed carbide phase can compriseelectrochemically processed sintered carbide scrap in an amount selectedfrom Table I, wherein the balance is filled by other reclaimed sinteredcarbide scrap, such as APT and/or zinc processed sintered carbide scrap.In some embodiments, the sintered cemented carbide article comprises avirgin powder phase, as described in Section I.

Additionally, the reclaimed carbide phase of sintered cemented carbidearticles can have an average grain size of 0.5 to 15 μm. In someembodiments, average grain size of the reclaimed carbide phase is 1-10μm or 0.5-5 μm. In other embodiments, average grain size of thereclaimed carbide phase is greater than 15 μm. Grain size of thereclaimed carbide phase can be selected according to severalconsiderations including, but not limited to, the desired mechanicalproperties of the sintered cemented carbide article and intended use ofthe sintered cemented carbide article.

As described herein, sintered cemented carbide articles also comprisemetallic binder. Compositional identity of the metallic binder isprovided in Section I herein. Additionally, metallic binder can bepresent in a sintered cemented carbide article in an amount selectedfrom Table II.

Sintered cemented carbide articles employing reclaimed carbide powdersdescribed herein may exhibit properties comparable to sintered articlesformed solely from virgin carbide powder compositions. In someembodiments, for example sintered cemented carbide articles describedherein exhibit a fracture toughness generally ranging from 5 to 20ksi(in)^(1/2) according to ASTM B771 Standard Test Method for Short RodFracture Toughness of Cemented Carbides. A sintered cemented carbidearticle, in some embodiments, has a fracture toughness selected fromTable III.

TABLE III Fracture Toughness [ksi(in)^(1/2)] - ASTM B771 10-20 11-1812-17 10-15 12-14In addition to fracture toughness, sintered cemented carbide articlesdescribed herein can exhibit transverse rupture strength of 250-650 ksiaccording to ASTM B406-Standard Test Method of Transverse RuptureStrength of Cemented Carbides. In some embodiments, a sintered cementedcarbide article has a transverse rupture strength selected from TableIV.

TABLE IV Transverse Rupture Strength (ksi) 300-650 350-600 400-600500-650Sintered cemented carbide articles described herein can exhibit hardnessof at least 80 HRA. In some embodiments, a sintered cemented carbidearticle has hardness of 80-95 HRA. Additionally the sintered cementedcarbide articles can have density of 14-15 g/cm³. For example, asintered cemented carbide article can have density of 14.1-14.8 g/cm³.Further, sintered cemented carbide articles described herein can be freeor substantially free of lower carbide phases, including eta phase[(CoW)C], W₂C and/or W₃C. In some embodiments, sintered cemented carbidearticles described herein are free of at least one of A-type porosityand B-type porosity. Moreover, sintered cemented carbide articlesdescribed herein can be free of free graphite (C-type porosity). In someembodiments, for example, a sintered cemented carbide article has aporosity designation of A00B00C00.

Sintered cemented carbide articles described herein can be cuttingelements or components of cutting elements for various applications. Insome embodiments, sintered cemented carbide articles include cuttinginserts for machining metal or alloys. In other embodiments, sinteredcemented carbide articles comprise interrupted cut tooling such asdrills, end mills and/or milling inserts. Additionally, sinteredcemented carbide articles described herein can be combined withultrahard materials including polycrystalline diamond (PCD), diamond,diamond-like carbon (DLC), cubic boron nitride and polycrystalline cubicboron nitride. For example, sintered cemented carbide articles describedherein can serve as a substrate or support to which PCD is sintered in ahigh temperature, high pressure process. In such embodiments, the layerof PCD can provide enhanced wear resistance leading to increasedlifetimes of cutting elements and/or wear parts employing sinteredcemented carbide compositions described herein. In some embodiments,sintered cemented carbide articles include earth boring and/or miningapparatus including earth boring bodies, bits and cutters.

III. Methods of Making Sintered Cemented Carbide Articles

In another aspect, methods of making sintered cemented carbide articlesare provided. In some embodiments, a method of making a sinteredcemented carbide article comprises providing a grade powder compositioncomprising a reclaimed carbide powder component in an amount of at least70 weight percent of the grade powder composition, the reclaimed carbidecomponent comprising electrochemically processed sintered carbide scrap.The grade powder composition also comprises metallic binder. The gradepowder composition is formed into a green article, and the green articleis sintered to provide the sintered cemented carbide article. Gradepowder compositions can have any composition and/or properties describedin Section I above. Additionally, sintered cemented carbide articlesformed according to methods described herein can have any compositionand/or properties described in Section II above.

The grade powder composition, in some embodiments, is provided by mixingthe reclaimed carbide powder component and the powder metallic binder.When desired, virgin carbide powder component can be added to themixture of the reclaimed carbide powder component and powder metallicbinder. The reclaimed carbide powder component, metallic binder and theoptional virgin carbide component can be present in the mixture inamounts described in Section I. The resulting mixture can be milled in aball mill or attritor. Milling of the mixture can result in particles ofthe reclaimed carbide component being coated with powder metallicbinder. When present, particles of the virgin carbide component are alsocoated with powder metallic binder.

The grade powder is formed or consolidated into a green article inpreparation for sintering. Any consolidation method can be employed notinconsistent with the objectives of the present invention. The gradepowder, for example, can be molded, extruded or pressed into a greenarticle. In several specific embodiments, the grade powder can be pillpressed or cold-isostatic pressed into the green article. In someembodiments, the grade powder is consolidated into a green article byone or more additive manufacturing techniques. Additive manufacturingtechniques contemplated herein include, but are not limited to, binderjetting, material jetting, laser powder bed, electron beam powder bedand directed energy deposition as described in ASTM F-42. The greenarticle can take the form of a blank or can assume near-net shape forthof the desired cutting element, including cutting insert, drill orendmill. In some embodiments, the green article is mechanically workedto provide the desired shape.

The green article is subsequently sintered to provide the article formedof sintered cemented carbide. The green article can be vacuum sinteredor sintered under an argon or hydrogen/methane atmosphere. During vacuumsintering, the green article is placed in a vacuum furnace and sinteredat temperatures of 1320° C. to 1500° C. In some embodiments, hotisostatic pressing (HIP) is added to the vacuum sintering process. Hotisostatic pressing can be administered as a post-sinter operation orduring vacuum sintering yielding a sinter-HIP process. The resultingsintered cemented carbide article can exhibit and fracture toughness andtransverse rupture strength values described herein.

In some embodiments, sintered cemented carbide articles havingcomposition and properties described herein are coated with one or morerefractory materials by PVD and/or CVD. In some embodiments, therefractory coating comprises one or more metallic elements selected fromaluminum and metallic elements of Groups IVB, VB and VIB of the PeriodicTable and one or more non-metallic elements selected from Groups IIIA,IVA, VA and VIA of the Periodic Table. For example, the refractorycoating can comprise one or more carbides, nitrides, carbonitrides,oxides or borides of one or more metallic elements selected fromaluminum and Groups IVB, VB and VIB of the Periodic Table. Additionally,the coating can be single-layer or multi-layer.

These and other embodiments are further illustrated by the followingnon-limiting examples.

EXAMPLE 1 Sintered Cemented Carbide Articles

Sintered cemented carbide articles of chemical composition listed inTable V were fabricated as follows. About 88 weight percent of tungstencarbide required for production of a sintered cemented carbide articlecame from electrochemically processed sintered WC scrap. The remaining12 weight percent of the tungsten carbide component came from zincreclaimed tungsten carbide. No virgin tungsten carbide was used in thesintered cemented carbide bodies of the present example. Properties ofthe electrochemically processed WC scrap used are provided in Table VI.

TABLE V Sintered Cemented Carbide Composition (wt. %) Ta Ti Nb Co WC 1.80.4 0.3 6 Bal.

TABLE VI Composition of Electrochemically Processed WC (wt. %) Ta Ti NbCo Fe Cr V WC 0.02 0.01 0 0.3 — 0.11 — Bal.

Average particle size of the electrochemically processed WC scrap wasapproximately 2 μm. The grade powder composition comprising theelectrochemically processed sintered tungsten carbide scrap, zincreclaimed tungsten carbide and fresh powder cobalt binder was ballmilled for 11 hours in heptane and spray dried to produce granulessuitable for pressing. Green blanks were pressed using the grade powderand vacuum sintered at 1482° C. for 45 minutes to produce fully densecompacts. Physical, microstructural and mechanical properties of thecompacts were comparable to sintered carbides made using virgin powderand are reported in Table VII.

TABLE VII Properties of Sintered Cemented Carbide Den- sity MS Pits &Anom- TRS (g/cm³) (%) Hc, Oe Porosity Flaw alies HRA (ksi) 14.64 88.2243 A02 + 0 0 92.5 349 B00 + C00

EXAMPLE 2 Sintered Cemented Carbide Articles

Sintered cemented carbide articles of chemical composition listed inTable VIII were fabricated as follows.

TABLE VIII Composition of Sintered Cemented Carbide Articles (wt. %) CoCr WC 6 0.4 Bal.

In Batch I, 100 weight percent of tungsten carbide required for theproduction of cemented carbides article came from electrochemicallyprocessed sintered WC scrap. No other source of tungsten carbide wasused in the production of the cemented carbide articles. Properties ofelectrochemically processed WC scrap are the same as provided in TableVI in Example 1. For comparison, Batch II was made side by side where 88weight percent of the required tungsten carbide was virgin WC and theremaining 12 weight percent came from zinc reclaimed WC. Grade powdersof Batch I and Batch II were each ball milled in heptane and spray driedto produce granules suitable for pressing. Batch I was ball milled for65 hours and Batch II was ball milled for 75 hours to achieve thecoercive force specification for the grade. Green blanks were pressedfrom Batch I and Batch II and vacuum sintered at 1482° C. for 45 minutesto produce fully dense compacts. Physical, microstructural andmechanical properties of the sintered compacts of Batch I and Batch IIare provided in Table IX.

TABLE IX Properties of Sintered Cemented Carbide Den- sity (g/ MS Pits &Anom- TRS Batch cm³) % Hc, Oe Porosity Flaw alies HRA (ksi) I 14.80 90.9261 A00 + 0 2 92.9 524.6 B00-5 II 14.85 88.3 260 A00 + 2 2 93.0 510.7B00-9As provided in Table IX, the sintered cemented carbide articles of BatchI comprising electrochemically processed WC scrap exhibited propertiessubstantially equivalent to the sintered cemented carbide articles ofBatch II employing 88 weight percent virgin WC.

Various embodiments of the invention have been described in fulfillmentof the various objects of the invention. It should be recognized thatthese embodiments are merely illustrative of the principles of thepresent invention. Numerous modifications and adaptations thereof willbe readily apparent to those skilled in the art without departing fromthe spirit and scope of the invention.

The invention claimed is:
 1. A sintered cemented carbide articlecomprising: a reclaimed carbide phase in an amount of at least 70 weightpercent of the sintered cemented carbide article; and metallic binder,wherein the reclaimed carbide phase comprises electrochemicallyprocessed sintered carbide scrap in an amount of 60-90 weight percent,and a balance of zinc processed sintered carbide scrap and/or ammoniumparatungstate processed sintered carbide scrap, and the sinteredcemented carbide article has a transverse rupture strength of 350-600ksi.
 2. The sintered cemented carbide article of claim 1, wherein thereclaimed carbide phase is present in an amount of 90-99 weight percentof the sintered cemented carbide article.
 3. The sintered cementedcarbide article of claim 1, wherein the electrochemically processedsintered carbide scrap comprises tungsten carbide.
 4. The sinteredcemented carbide article of claim 1 further comprising at least onemetal carbide selected from the group consisting of Group IVB metalcarbides, Group VB metal carbides and Group VIB metal carbides.
 5. Thesintered cemented carbide article of claim 1 having fracture toughnessof 5-20 ksi(in^(1/2)).
 6. The sintered cemented carbide article of claim1, wherein the electrochemically processed sintered carbide scrap has anaverage particle size of 0.5 μm to 15 μm.
 7. The sintered cementedcarbide article of claim 1 having density of 14-15 g/cm³.
 8. Thesintered cemented carbide article of claim 1 having hardness of 80-95HRA.
 9. The sintered cemented carbide article of claim 1 having theshape of a cutting element.
 10. The sintered cemented carbide article ofclaim 1 having a transverse rupture strength of 400-600 ksi.
 11. Thesintered cemented carbide article of claim 1 having fracture toughnessof 10-20 ksi(in^(1/2)).
 12. The sintered cemented carbide article ofclaim 1, wherein the sintered cemented carbide article is free of lowercarbide phases.
 13. A sintered cemented carbide article comprising: avirgin carbide phase; a reclaimed carbide phase in an amount of at least70 weight percent of the sintered cemented carbide article; and metallicbinder, wherein the reclaimed carbide phase comprises electrochemicallyprocessed sintered carbide scrap in an amount of 60-90 weight percent,and a balance of zinc processed sintered carbide scrap and/or ammoniumparatungstate processed sintered carbide scrap, wherein the sinteredcemented carbide article has a transverse rupture strength of 350-600ksi.
 14. The sintered cemented carbide article of claim 13 havingfracture toughness of 10-20 ksi(in^(1/2)).
 15. A sintered cementedcarbide article comprising: a reclaimed carbide phase in an amount of atleast 70 weight percent of the sintered cemented carbide article; andmetallic binder, wherein the reclaimed carbide phase compriseselectrochemically processed sintered carbide scrap in an amount of 50-85weight percent, and a balance of zinc processed sintered carbide scrapand/or ammonium paratungstate processed sintered carbide scrap, and thesintered cemented carbide article has a transverse rupture strength of350-600 ksi.
 16. A sintered cemented carbide article comprising: avirgin carbide phase; a reclaimed carbide phase in an amount of at least70 weight percent of the sintered cemented carbide article; and metallicbinder, wherein the reclaimed carbide phase comprises electrochemicallyprocessed sintered carbide scrap in an amount of 50-85 weight percent,and a balance of zinc processed sintered carbide scrap and/or ammoniumparatungstate processed sintered carbide scrap, wherein the sinteredcemented carbide article has a transverse rupture strength of 350-600ksi.